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Wednesday, August 26th 2015, 8:29pm

Howl from drip irrigation system.

Hi there,

I have a drip irrigation system at my home. It has four zones, 1 is a drip feed in the front yard, 2 and 3 are sprinklers in the back, 4 is drip in the back. When zone 1 and only that zone is active, the valve/solenoid makes a very loud, high pitched whine. It's *not* a banging sound, nor is it buzzing. In case it makes a difference to anyone, I make the tone to be fairly pure, with a primary frequency of about 410 Hz, and in excess of 80dB. I don't see any leaks, and the system seems to be working, but the noise is loud enough that it could easily annoy the neighbors, and it might be a symptom of a budding problem. The system has been in the ground for at least a decade, and I haven't made any recent changes to any part of that particular zone, but it's always possible that a piece of debris has gotten into the line somewhere or something like that.

I'm guessing the valve or solenoid is telling me it will eventually fail, but I'm curious if (a) someone with more experience than I knows what's really going on, and (b) what is the actual cause of this particular noise, which is one I can't identify.

Thanks in advance.



Posts: 2,342

Location: USA


Thursday, August 27th 2015, 4:42am

It could be the valve but check the pressure reducer. I've seen those things squeal like crazy even brand new.
Sometimes if there's not enough flow going through the reducer it will squeal.
You could try opening the end of the drip line and see if the squealing stops.

Maybe clean the filter to make sure there's full flow.

You could try fiddling with the flow control of the valve. What valve and pressure reducer are installed?

I've recently started installing the Rainbird pressure reducer/filter. I'm super happy with them. No squealing yet.




Thursday, August 27th 2015, 4:59pm

Thanks for the response.

The noise is definitely coming from the valve, no question. I removed an emitter at the end of the line and the noise stopped. The flow coming out there was quite healthy. I replaced that emitter with the highest rate one I had handy, 2gal/min, and (a) the noise returned and (b) the rest of the emitters on the line were starved.

I took the thing apart and cleaned it out and reassembled it. I detected no blockages and no damage. I reassembled it and the only change is that the pitch of the howl seemed a tiny bit lower.

The valve is an Irritrol 205t. I don't see a pressure reducer or filter on the line, and there just isn't a lot of distance between the pressure breaker valve and the valve in question. If there's one there, I'll need a shovel to check it out. However, at the very least, the flow seems robust.

I could try to reduce the flow by partially shutting the service at the pressure breaker valve, but (a) while doing that while the zone is being fed eliminates the noise, it's only temporary. On the next cycle at the new pressure setting the noise returns, and (b) this starves the sprinklers in the back yard.



Posts: 2,342

Location: USA


Thursday, August 27th 2015, 6:55pm

There's not much to a 205 valve. I suppose you could install a new diaphragm and see what happens. It's not the solenoid.
Maybe you should take out your pressure reducer and install the Rainbird reducer/filter I posted earlier.
Adding a few emitters or installing emitters with a higher flow would work also.

I just thought of something else. Sometimes there's a fitting at the beginning of the drip line which screws on. Inside that sometimes is a hose washer with a screen built into it. It's a pretty lame way of keeping debris out but you never know. Take a look.

This post has been edited 1 times, last edit by "mrfixit" (Aug 27th 2015, 7:11pm)

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